From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754824AbYAXEYR (ORCPT ); Wed, 23 Jan 2008 23:24:17 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752938AbYAXEYD (ORCPT ); Wed, 23 Jan 2008 23:24:03 -0500 Received: from fgwmail5.fujitsu.co.jp ([192.51.44.35]:35189 "EHLO fgwmail5.fujitsu.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752882AbYAXEYB (ORCPT ); Wed, 23 Jan 2008 23:24:01 -0500 Date: Thu, 24 Jan 2008 13:23:53 +0900 From: KOSAKI Motohiro To: linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: [RFC][PATCH 6/8] mem_notify v5: (optional) fixed incorrect shrink_zone Cc: kosaki.motohiro@jp.fujitsu.com, Marcelo Tosatti , Daniel Spang , Rik van Riel , Andrew Morton , Alan Cox In-Reply-To: <20080124130348.1760.KOSAKI.MOTOHIRO@jp.fujitsu.com> References: <20080124130348.1760.KOSAKI.MOTOHIRO@jp.fujitsu.com> Message-Id: <20080124132249.1772.KOSAKI.MOTOHIRO@jp.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit X-Mailer: Becky! ver. 2.42 [ja] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org on X86, ZONE_DMA is very very small. It is often no used at all. Unfortunately, when NR_ACTIVE==0, NR_INACTIVE==0, shrink_zone() try to reclaim 1 page. because zone->nr_scan_active += (zone_page_state(zone, NR_ACTIVE) >> priority) + 1; ^^^^^ it cause unnecessary low memory notify ;-) ChangeLog v5: new --- mm/vmscan.c | 21 ++++++++++++++++----- 1 file changed, 16 insertions(+), 5 deletions(-) Index: b/mm/vmscan.c =================================================================== --- a/mm/vmscan.c 2008-01-18 14:18:27.000000000 +0900 +++ b/mm/vmscan.c 2008-01-18 14:49:06.000000000 +0900 @@ -948,7 +948,7 @@ static inline void note_zone_scanning_pr static inline int zone_is_near_oom(struct zone *zone) { - return zone->pages_scanned >= (zone_page_state(zone, NR_ACTIVE) + return zone->pages_scanned > (zone_page_state(zone, NR_ACTIVE) + zone_page_state(zone, NR_INACTIVE))*3; } @@ -1214,18 +1214,29 @@ static unsigned long shrink_zone(int pri unsigned long nr_inactive; unsigned long nr_to_scan; unsigned long nr_reclaimed = 0; + unsigned long tmp; + unsigned long zone_active; + unsigned long zone_inactive; if (scan_global_lru(sc)) { /* * Add one to nr_to_scan just to make sure that the kernel * will slowly sift through the active list. */ - zone->nr_scan_active += - (zone_page_state(zone, NR_ACTIVE) >> priority) + 1; + zone_active = zone_page_state(zone, NR_ACTIVE); + tmp = (zone_active >> priority) + 1; + if (unlikely(tmp > zone_active)) + tmp = zone_active; + zone->nr_scan_active += tmp; nr_active = zone->nr_scan_active; - zone->nr_scan_inactive += - (zone_page_state(zone, NR_INACTIVE) >> priority) + 1; + + zone_inactive = zone_page_state(zone, NR_INACTIVE); + tmp = (zone_inactive >> priority) + 1; + if (unlikely(tmp > zone_inactive)) + tmp = zone_inactive; + zone->nr_scan_inactive += tmp; nr_inactive = zone->nr_scan_inactive; + if (nr_inactive >= sc->swap_cluster_max) zone->nr_scan_inactive = 0; else